Preheat oven to 350 F.
In a large pot of boiling water blanch the turnips (5 min) or steam in a steamer.
In the same pot, blanch the potatoes (5 min) or steam.
Also blanch the greens and then squeeze out excess moisture .
To assemble the dish, rub a large casserole with butter and then the garlic clove.
Layer half of the potatoes and half of the turnips. Put the greens in next and sprinkle with salt, pepper and thyme. Sprinkle on the grated cheese. Next put the remaining turnips and top with remaining potatoes. Drizzle with the cream.
If you like, sprinkle more cheese on top. Bake uncovered 50-60 minutes. The top will be crisp and golden.
Adapted from “Bistro Cooking” by Patricia Wells.